The invention relates to a side gas bag restraint system for a vehicle having a roof frame and vehicle columns extending upwardly to the roof frame and having side windows, the roof frame and the vehicle columns being covered by at least one lining.
Side gas bags having a large area, also known as window bags, are intended to restrain the head of the occupant in a side impact or in a roll-over of the vehicle, by covering the side windows. At the same time the side gas bag is to be kept as stable as possible in order to be able to take up the forces applied by the impacting head of the occupant. The extremely short unfolding time which is available within which the gas bag must be completely unfolded and optimally positioned is also very problematic. In order to shorten this positioning and the unfolding process or make them more able to be predetermined, the EP 0 847 904 A1 suggests arranging one guide rod along the roof frame and one along the B-column, the rods each provided behind a lining. A triangular side gas bag is then to be tensioned between these guide rods, on which it is fastened so as to be slidably displaceable. In order to accelerate the unfolding, additional drives are provided, engaging directly on the gas bag, which are intended to engage on the gas bag and pull it out from its covering. Such additional drive elements are, however, very expensive and difficult to accommodate in the vehicle. The guide rods arranged behind the lining do not offer an optimum reliability in function in the case of restraint. With the impact of the head onto the gas bag in fact the deformation of the guide rods can occur. In addition, it is disadvantageous that the gas bag must move along between the lining, covering the rods to the passenger compartment, and the roof frame or the B-column. As the lining must be arranged very close to the roof frame or the B-column, in order to avoid intrusive gaps, the gas bag must overcome an increased friction in order to move along between the lining and the roof frame or the B-column.
DE 196 54 490 A1 contains one embodiment according to which a flexible, closed ring circumscribes a thick, hose-shaped gas bag in the circumferential direction, the ring being fixed to the gas bag at attachment points. Two tensioning straps extend from the ring in opposite directions to the A- and the B-pillar of the vehicle. In order to achieve a tensioning effect in the unfolded state of the gas bag, the geometry of the gas bag and the length of the tensioning straps have to be exactly adapted to the geometry of the vehicle. Further, as the gas bag and the tensioning straps are extending adjacent to each other behind the lining, there exists a risk that the gas bag intertwines with the straps or becomes entangled resulting in a an incomplete or decelerated unfolding process.
The invention relates to a side gas bag restraint system in which the guide for the gas bag is able to be produced at an extremely favorable cost and a slight resistance is offered to the unfolding of the gas bag. The system according to the invention ensures a complete, fast unfolding of the gas bag.
The side gas bag restraint system according to the invention comprises a curtain-like gas bag covering at least one side window of the vehicle to at least a major extend in an unfolded state of the gas bag and being attached to the vehicle at fastening points, and comprises an elongated guide device to which the gas bag is displaceable fastened and along which the gas bag moves itself on unfolding of the gas bag. The guide device is arranged behind a lining and extends downwardly along a vehicle column in the unfolded and in the folded state of the gas bag. The guide device has two stationary fastening ends at which the guide device is fixed to the vehicle and is constructed so as to be so flexible that the gas bag draws the guide device out from the lining on unfolding of the gas bag. The gas bag is tensioned between its fastening points and the guide device when unfolded. According to the invention both fastening ends of the guide device are stationary, i.e. vehicle-fixed so that the movement of the guide device is limited when the gas bag is inflated.
The guide device is to be exposed by the gas bag itself such that the lining no longer acts as an obstacle during the unfolding of the gas bag and the sliding of the gas bag along the guide device. The guide device is preferably drawn through between the lining and the sheet metal part of the vehicle on which the lining is arranged, at least over the part along which the gas bag slides.
The guide device is preferably a flexible belt with stationary fastening ends in the vehicle. The gas bag tensions the flexible belt in the inflated state between the fastening ends, so that the flexible belt stabilizes and holds the gas bag.
According to one development, the guide device extends in a non-linear manner between its stationary fastening ends, arrested on the vehicle, in the non-unfolded state of the gas bag, whereby a withdrawal of the guide device out from the lining is made possible.
In the unfolded state, the gas bag extends from the at least one stationary fastening point on such vehicle column at which the guide device is not arranged to and along the roof frame to pass at least one stationary fastening point on the roof frame and extends further to an upper end of the column along the guide device extends. Thus, the gas bag cannot intertwine with the guide device as both are not arranged adjacent to each other behind the lining.
According to one development of the invention, provision is made that the gas bag is a gas bag covering a side window of the vehicle and the guide device extends along a vehicle column (A-, B- or C-column). For the optimum guidance of the gas bag during the unfolding, the guide device is preferably arranged behind the lining of the B-column so as to run vertically up to the roof frame. Here, the guide device extends at its upper end a further distance along the roof frame. This end is already drawn out from the lining at the start of the unfolding process through the gas bag which is folded along the roof frame.
The gas bag can be connected with the guide device at several points, in particular, however, in the region of its lower edge corner region in the folded state, where a slide connection (e.g. an eye) is arranged.
An advantageous and simple possibility for drawing the guide device out from the lining through the gas bag consists in positioning a connecting line between the fastening ends of the guide device at least in the region of the unfolded gas bag outside the lining.
According to the preferred embodiment of the invention, the gas bag is tensioned in the unfolded state along its lower edge between a fastening point on the vehicle and the guide device.